Smart traders and investors know there is a substantial risk with any trade or investment regardless of the underlying technology.
There's going to be a lot of angry people like nowadays during Bitcoin crash period.
People who were lucky enough to invest when advised a while ago but too stupid to realize it's not sustainable, too hubristic to realize their downfall will be at their own hands and will blame others for not understanding bitcoin.
Truth is bitcoin and other altcoins made people a lot of money, somewhere smart enough to see it for what it is, some did it for fun and many just followed the crowds which some got in at the right time, some did not.
You can spot the one's who don't understand the very basics of investment and just ride the bitcoin gravy train thinking they were somehow more intelligent than those that slept through it, the ones that think others just "don't get it" the bitsheep, they're the ones that lash out at others, call people jealous and just generally get pissed at those who view it for what it is and when it falls the'll blame the governments, hackers and all manner of excuses and not think for a minute about they're own short comings.
In these schemes always a few take 99% of the money so that most just lose money ...
The blockchain is a serious technology and future but did not work in crypto mining coins, greed destroyed the whole focus of this technology. When it breaks, there will be a lot of people who today find themselves billionaires in bitcoins coming back to misery in seconds.
Both South Korea and China made bitcoin-related regulations ... South Korea nearly banning it, and China restricting it to smaller transactions between people. Essentially. News has many more details. The South Korea actions are what triggered the sell-off ...
Bitcoin has been well over the market in South Korea trading for over 20K often recently. The drop is an expected reaction.
Unless you're a day trader it's nothing to worry about. And if you are a day trader an opportunity if you time it right.